Deciphering the alternating synergy between interlayer Pt single-atom and NiFe layered double hydroxide for overall water splitting

Single-atom catalysts (SACs) have enormous significance in heterogeneous catalysis. However, understanding how SACs function at the molecular level remains a huge challenge. Here, we report a general approach to anchor Pt single-atom intercalated in layered double hydroxide (LDH) and decipher the alternating synergy between Pt single-atom and Ni3Fe LDH support for overall water splitting. Aided with Tafel slope, interface species evolution and control experiments, operando electrochemical impedance spectroscopy (EIS) can distinguish interface charge transport and elementary reactions during hydrogen and oxygen evolution reactions (HER and OER). For HER, interlayer Pt single-atom vastly enhances electron transferability of LDH support, and Ni3Fe LDH support accelerates water dissociation, thus resulting in a mixture of mechanisms (Heyrovsky-Volmer and Tafel-Volmer) in 1 M KOH. For OER, interlayer Pt single-atom not only prompts active phase transition from NiFe LDH to Ni2+delta Fe3+zeta OxHy, but also optimizes OER intrinsic activity of Ni2+delta-O-Fe(3+zeta )in Ni2+delta Fe3+zeta OxHy. Overall, we provide a referential paradigm for SACs synthesis strategy and unscrambling its alternating synergy.

Automated summary

This study presents a novel approach to anchor Pt single-atoms into layered double hydroxide, deciphering the synergy between Pt single-atoms and Ni3Fe LDH support during water splitting. Operando electrochemical impedance spectroscopy is used to distinguish interface charge transport and reactions during the hydrogen and oxygen evolution processes, unveiling the mechanisms of Pt single-atoms and LDH support in catalytic reactions.